Prepare release v0.12.0 (#220)

## heroku/python

### Changed

- Updated pip from 24.0 to 24.1.1. ([#219](#219))
- Updated setuptools from 70.0.0 to 70.1.1. ([#218](#218))
- Buildpack detection now recognises more types of Python-related files. ([#215](#215))

Co-authored-by: heroku-linguist[bot] <136119646+heroku-linguist[bot]@users.noreply.github.com>

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.12.0] - 2024-06-27
+
 ### Changed
 
 - Updated pip from 24.0 to 24.1.1. ([#219](https://github.com/heroku/buildpacks-python/pull/219))
@@ -151,7 +153,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Initial implementation. ([#3](https://github.com/heroku/buildpacks-python/pull/3))
 
-[unreleased]: https://github.com/heroku/buildpacks-python/compare/v0.11.0...HEAD
+[unreleased]: https://github.com/heroku/buildpacks-python/compare/v0.12.0...HEAD
+[0.12.0]: https://github.com/heroku/buildpacks-python/compare/v0.11.0...v0.12.0
 [0.11.0]: https://github.com/heroku/buildpacks-python/compare/v0.10.0...v0.11.0
 [0.10.0]: https://github.com/heroku/buildpacks-python/compare/v0.9.0...v0.10.0
 [0.9.0]: https://github.com/heroku/buildpacks-python/compare/v0.8.4...v0.9.0

buildpack.toml

@@ -2,7 +2,7 @@ api = "0.10"
 
 [buildpack]
 id = "heroku/python"
-version = "0.11.0"
+version = "0.12.0"
 name = "Heroku Python"
 homepage = "https://github.com/heroku/buildpacks-python"
 description = "Heroku's buildpack for Python applications."